If xy = 4, prove that 
.
Given xy = 4
On differentiating y with respect to x, we get
We know 
Now, we will evaluate the LHS of the given equation.
However, xy = 4
[∵ xy = 4]
Thus, 
73
If xy = 4, prove that .
Given xy = 4
On differentiating y with respect to x, we get
We know
Now, we will evaluate the LHS of the given equation.
However, xy = 4
[∵ xy = 4]
Thus,